another challanging rediret

It looks like you're pretty close. You might want to do a couple things different.

First, I'd recommend using the HTTP::uri command, rather than doing full on HTTP::redirects, as they shouldn't be necessary.

Second, rather than checking for certain directories, if you truly want to append "index.html" to all requests coming through this virtual, it's done with relative ease like this:

when HTTP_REQUEST {
  if { not ( [HTTP::uri] ends_with "/" ) } {
    set newURI "[HTTP::uri]/index.html"
  } else {
    set newURI "[HTTP::uri]index.html"
  }
  HTTP::uri $newURI
}

This should modify the URI to append index.html to whatever was currently there.

HTH,

Colin